Although there were no mechanical changes from 1992 to 1993 (aside from hypereutectic pistons replacing the previous forged aluminum pistons), both the horsepower and torque ratings dropped for ‘93 - horsepower by 20 and torque by 25. The reduced ratings were influenced by a stack-up of minor mechanical changes and by changes to Ford’s engine evaluation processes. Dictated mainly by emissions, fuel economy and customer satisfaction requirements, a series of mechanical revisions had been made since Ford initially assigned the engine’s 225-horsepower rating for 1987. These include a restrictive resonator added to the inlet tract (1987-1993) that produced a 5-7 horsepower loss. The small camshaft profile change in 1989 reduced HO output by 3 horsepower. The restrictive mass airflow meter in the inlet tract introduced in 1989 yields 2-3 horsepower less than the speed density system. Some minor exhaust system revisions made between 1987-1993 also add up to another small reduction in engine output. The second contributing factor in the re-rating of the ‘93 V8 involved changes in the processes that Ford used to select engines for testing and the engine’s state of dress (with all engine-driven accessories) during testing. Combined with the ‘87-93 mechanical revisions, the revised-for-1993 testing procedures add up to the ‘93 model year’s reduced output ratings.
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